Prevention of child and adult obesity is a national public health priority. Optimal interventions would target young children and their overweight parents to capitalize on the formation of healthy eating habits and increased physical activity in the child, target weight loss strategies in the parent, and maximize mutual reinforcement of the family members'healthy behaviors. Such interventions would: 1) be population based, 2) target children at risk during a key developmental period, 3) target overweight parents at a time when they are motivated to engage in behavioral change and 4) target healthy eating and physical activity as well as parenting skills necessary to implement such changes. This application addresses these needs by 1) using several, complementary, avenues of participant recruitment, 2) targeting 2-5 year old preschoolers through their mothers who are a) overweight and b) have just delivered a second or subsequent child, 3) capitalizing on the arrival of the new baby as a "teachable moment" to initiate behavioral change, 4) providing a mail and telephone-assisted intervention that addresses both parenting skills and behavioral weight management, and 5) utilizing a housebuilding metaphor with the characters Carl and Carla the Carpenters acting to integrate the intervention and deliver healthy lifestyle messages. In a five-year trial, 400 mother/preschooler dyads in the Triangle and Triad areas of North Carolina will be randomized to: 1) the CONTROL ARM: 12 monthly newsletters with general family health tips, and monetary incentives to complete assessments;and 2) the KAN-DO (Kids &Adults Now-Defeat Obesity) INTERVENTION: the monthly newsletter and assessment incentives, 8 modules of an interactive, mail-based intervention kit supported by telephone counseling and two group meetings. Primary aims are to evaluate whether KAN-DO, through improved parenting skills, can achieve healthy eating and increased physical activity and, ultimately, healthy weight attainment in the preschooler. Secondary aims evaluate KAN-DO's effect on behavior and weight change in the mother. We will also assess whether behavior and weight changes are greater a) where the mother has improved parenting skills, and b) among families for whom the birth of a subsequent child is more of a "teachable moment". Participants will be surveyed at baseline (3 months postpartum), 12 and 24 months post-baseline. Extended follow-up will enable evaluation of long-term benefits, and if effective, the KAN-DO intervention can be disseminated broadly.